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For a high-volume manufacturer of consumer products, developing a new production process represents a challenging endeavor. Existing production levels must be maintained while phasing in new machine tools, and the organization must adapt simultaneously to changes in workflow and job assignments. Because new products are often developed concurrently with day-to-day production operations, successful manufacturers recognize the advantage of prototyping machining processes at the same time that they prototype parts.

One such manufacturer is Tecumseh Products Company (Tecumseh, Michigan), perhaps best known as a producer of gasoline engines and power trains for lawn equipment and recreational vehicles. Founded in 1930 by Ray W. Herrick, the firm’s business was initially focused on the production of automotive parts. By the end of World War II, however, Tecumseh had become an important manufacturer of compressors for mechanical refrigerators. Over the years, this segment of the firm’s business has expanded to include compressors for various types of cooling applications.

Today, the company has more than 30 principal locations in the United States and around the world. Manufacturing hermetic compressors for air conditioning and refrigeration products currently represents more than 60 percent of Tecumseh’s business, while engine and power train production accounts for approximately 33 percent. The company’s compressor products include small units for household refrigerators and dehumidifiers, as well as larger units for commercial air conditioning systems. Tecumseh also manufactures various types of pumps for industrial, commercial, agricultural and marine applications.

Given the key role of compressor production in the company’s success, maintaining an efficient and competitive manufacturing process is crucial. Demonstrating its commitment to adopt new manufacturing technologies and techniques, the company recently purchased a Mazak multi-process machine for operations at its Dundee Research Division (Dundee, Michigan). After investigating the machine’s capabilities at the Mazak National Technology Center (Florence, Kentucky), Tecumseh’s management team decided that the Integrex 300-IISY was well suited to the company’s needs. “Not only was this machine selected for R&D work, but also for technology evaluation,” says Michael Bourg, general manager of the firm’s development laboratory.

Part And Process

The Dundee facility has approximately 40 employees, including one CAD operator, one CAM operator and seven programmers. The company uses a solid-model programming system with Unigraphics software. The research division’s work includes machining compressor, engine, motor and pump components for testing purposes, as well as some that are used in new products. For this reason, the machine shop strictly produces short runs of parts that are subject to frequent design changes. In this type of environment, the multi-process machine’s abilities to complete parts in single setups and to switch rapidly from running one part program to the next are particularly advantageous.

The internal structure of a hermetic compressor is designed to retain tiny molecules of refrigerant gas. For this reason, the compressor’s main bearing must be machined to extremely close tolerances. Tecumseh engineers constantly develop new bearing designs to perform this function more efficiently, and a significant portion of the Dundee facility’s work involves developing and testing new versions of this part. The company’s recent experience in producing these prototypes suggests that the multi-process machine has great potential to enhance Tecumseh’s overall manufacturing scheme.

In the past, manufacturing these bearings required two lathe operations, two machining center operations and four inspection programs. This process involved multiple machine setups and a substantial amount of human intervention. The multi-process machine now enables the company to reduce this process to only one setup and one CMM operation. Pursuant to the acquisition of a new machine, Tecumseh’s CEO, Todd Herrick, established the ambitious goal of going from art to part in only 2 weeks. But the company now aims to exceed even these high expectations.

“With the Integrex we have achieved that goal and are now working toward a 1-week time frame,” says Mr. Bourg. In terms of efficiency, he says, “We’ve had a 60 to 70 percent reduction in our overall processing time for this component.” In addition to time saved, eliminating multiple setups has a positive impact on the products that Tecumseh develops. Besides substantially reducing human errors, it also avoids variations due to tolerance stackups. “This enables us to hold tighter tolerances and to produce higher-quality parts,” says Mr. Bourg.

Planning For The Future

While its research facility continues to evaluate the performance of the new machine, Tecumseh is prototyping production processes for potential applications throughout its manufacturing operations. Ultimately, the company’s management aims to create more efficient and flexible manufacturing operations that fully exploit the key advantages of this technology.

Proving out these new processes in a research environment certainly makes sense for large manufacturers such as Tecumseh that maintain multinational operations. But the company’s recent experience also suggests that a similar strategy is not beyond the reach of smaller manufacturers, particularly those who share the need for concurrent research, development and production. As metalworking firms that serve varied business segments increasingly adopt multi-process machines, it’s apparent that the justification for using this technology doesn’t necessarily depend on the relative scale of operations. Regardless of the quantity or type of parts produced, manufacturers widely consider this capability to represent an important competitive advantage.

Advantages Of Multitasking

Reduced part cost: Because parts may be completely machined in single setups, a shop needs fewer machines and operators. This reduces the direct cost of electricity and conserves floor space.

Increased throughput: When completed on a single machine, parts may be shipped to customers on a more frequent basis, regardless of the quantity ordered. Although cycle times are sometimes longer for multi-process machines than would be the case when using conventional, single-process machines, the greater throughput represents an important advantage in a shop’s overall production process.

More uniform shipments and improved cash flow: manufacturers can ship smaller lot sizes on a more steady basis without the payment gaps associated with deliveries of larger lots of parts. This facilitates a just-in-time production strategy by reducing work-in-progress and inventory.

Improved design and accuracy of parts: Designing workpieces to be completed on a single machine allows the engineer to avoid geometrical inconsistencies and tolerance stack-ups that degrade part quality. This allows complex part designs or multiple-part assemblies to be designed for machining out of single pieces of stock.

Fixture and tooling reduction: With the capability to machine the features of many parts in a single chucking, the need for complex and costly fixtures is eliminated. The availability of multipurpose cutting tools and the Integrex’s versatile toolholder design also reduces the total number of tools needed.

Unattended operation: Multi-process machines are well suited to lights-out operation, particularly when combined with automatic loading or pallet systems.

Reduction of non value-added time: Operations typical of conventional machining processes—part handling, queuing, refixturing and idle machine time—are eliminated. Because many turned and milled features may be automatically probed without removing parts from the machine, substantial time for transferring parts to inspection and for setting up CMMs is eliminated.

Compressing lead times: When considering overall efficiency in terms of the time elapsed from receipt of an order until the customer takes delivery, multi-process machines offer significant advantages. This way of thinking assumes that cycle time comprises not only the machine time, but also the entire process of production, shipment, delivery and remittance by the customer.

Increase profitability: Because multi-process machines enable manufacturers to offer customers fast turnaround on orders regardless of size or frequency, flexibility is created that enables shops to accept high-value, rush orders for small quantities of parts. This represents an important competitive advantage in relation to shops that operate only single-process machine tools.